With a mandolin, cut the potatoes into very thin slices. Rinse and drain. Place the slices in a bowl and cover with cold water and the vinegar. Let soak for 30 minutes or overnight.
Preheat the oil in the deep fryer to 350°F (180°C). Line a baking sheet with paper towels.
Drain the potato slices and dry in a salad spinner or on a clean cloth.
Fry one-quarter of the potato slices at a time for 2 to 3 minutes, or until golden brown, turning them regularly. Beware of splattering. Drain on the paper towels and season lightly with salt.
The chips will keep for about 1 week in an airtight container stored in a cool, dry place.
The vinegar in this recipe is optional, but it contributes to a crispier chip with more intense flavour.
The more stable the temperature of the oil, the better the result. Therefore, we recommend frying the potato slices in small batches.